Abstract: Provided herewith are methods and apparatus for optimizing an atrioventricular (AV) pacing delay interval. One manner described involves dynamically programming an AV interval in cardiac resynchronization therapy (CRT) device having a rate-adaptive AV (RAAV) feature in such a way that not less than a minimum AV interval is maintained. That is, the AV interval is not allowed to be reduced so much that the P-wave is truncated by the QRS complex. In this form of the invention, the AV interval is reduced by one millisecond per one bpm increase in heart rate (and vice versa for reducing heart rate) but maintained at a value calculated from the end of the P-wave (PWend) and the beginning of the QRS complex (QRSbeg) or delivery of a ventricular pacing stimulus or to the end of the end of the QRS complex (QRSend).

Abstract: A leadless pacing device (LPD) includes a motion sensor configured to generate a motion signal as a function of heart movement. The LPD is configured to analyze the motion signal within an atrial contraction detection window that begins an atrial contraction detection delay period after activation of the ventricle, and detect a contraction of an atrium of the heart based on the analysis of the motion signal within the atrial contraction detection window. If the LPD does not detect a ventricular depolarization subsequent to the atrial contraction, e.g., with an atrio-ventricular (AV) interval beginning when the atrial contraction was detected, the LPD delivers a ventricular pacing pulse.

Abstract: A medical device and associated method control the delivery of a cardiac pacing therapy including selecting left ventricular pacing sites for delivering the therapy. The left ventricular pacing sites are selected by delivering pacing pulses to a patient's left ventricle at multiple pacing sites one at a time and determining right ventricular activation times in response to the pacing pulses being delivered at each of the pacing sites. A left ventricular pacing site is selected in response to the determined right ventricular activation times.

Abstract: A medical device and associated method classify candidate pacing electrode sites for delivering pacing pulses to a patient's heart. A first morphology template is established and stored in memory of the device. A processor is configured to determine a cardiac signal morphology in response to delivering pacing pulses at a candidate pacing site in a first heart chamber. The processor compares the determined cardiac signal morphology to the first morphology template. The pacing site in the first heart chamber is classified in response to the comparing of the determined cardiac signal morphology and the first morphology template.

Abstract: Provided herewith are methods and apparatus for optimizing an atrioventricular (AV) pacing delay interval based upon ECG-based optimization is calculated as a linear function of P-wave duration, sensed PR (intrinsic) interval, sensed or paced QRS duration and heart rate. Since the relationship among these parameters is linear, once the coefficients are solved (which can be any value, including null) with reference to a known optimized AV interval (AVopt) such as from an echocardiographic study, an AVopt value can be dynamically adjusted in an ambulatory subject. The various combinations of values can be loaded into a look up table or calculated automatically. And, since some of the parameters do not typically change much over time they can be determined acutely and fed into the equation while the other values can be measured frequently. The parameter values can be measured by an implantable medical device such as a dual- or triple-chamber pacemaker.

Abstract: A medical device and associated method for controlling a cardiac pacing therapy sense a first cardiac signal including events corresponding to cardiac electrical events and a second cardiac signal including events corresponding to cardiac hemodynamic events. A processor is enabled to measure a cardiac conduction time interval using the first cardiac signal and control a signal generator to deliver a pacing therapy. A pacing control parameter is adjusted to a plurality of settings during the pacing therapy delivery. A hemodynamic parameter value is measured from the second cardiac signal during application of each of the control parameter settings. The processor identifies an optimal setting from the plurality of settings and solves for a patient-specific equation defining the pacing control parameter as a function of the cardiac conduction time interval.

Abstract: Techniques and systems for monitoring cardiac arrhythmias and delivering electrical stimulation therapy using a subcutaneous device (e.g. subcutaneous implantable (SD)) is described. In one or more other embodiments, SD is implanted into a patient's heart. Electrical signals are then sensed which includes moderately lengthened QRS duration data from the patient's heart. A determination is made as to whether cardiac resynchronization pacing therapy (CRT pacing) is appropriate based upon the moderately lengthened QRS duration in the sensed electrical signals. The CRT pacing pulses are delivered to the heart using electrodes. In one or more embodiments, the SD can switch between fusion pacing and biventricular pacing based upon data (e.g. moderately lengthened QRS, etc.) sensed from the heart.

Abstract: Techniques and systems for monitoring cardiac arrhythmias and delivering electrical stimulation therapy using a subcutaneous device (e.g. subcutaneous implantable (SD)) and a leadless pacing device (LPD) are described. In one or more embodiments, a computer-implemented method includes sensing a first electrical signal from a heart of a patient through a SD. The first signal is stored into memory and serves as a baseline rhythm for a patient. Subsequently, a second signal is sensed from the heart through the SD. A cardiac condition can be detected within the sensed second electrical signal through the SD. A determination is made as to whether cardiac resynchronization therapy (CRT) is appropriate to treat the detected cardiac condition. A determination can then be made as to the timing of pacing pulse delivery to cardiac tissue through a leadless pacing device (LPD). The LPD receives communication from the SD requesting the LPD to deliver CRT to the heart.

Abstract: Cardiac resynchronization therapy (CRT) delivered to a heart of a patient may be adjusted based on detection of a surrogate indication of the intrinsic atrioventricular conduction of the heart. In some examples, the surrogate indication is determined to be a sense event of the first depolarizing ventricle of the heart within a predetermined period of time following the delivery of a fusion pacing stimulus to the later depolarizing ventricle. In some examples, the CRT is switched from a fusion pacing configuration to a biventricular pacing configuration if the surrogate indication is not detected, and the CRT is maintained in a fusion pacing configuration if the surrogate indication is detected.

Abstract: Methods and/or devices may be configured to track effectiveness of pacing therapy by monitoring two or more electrical vectors of the patient's heart during pacing therapy and analyzing at least one feature of a morphological waveform within each of the two or more electrical vectors.

Abstract: A method and system for preventing phrenic nerve injury during a cardiac ablation procedure. The method generally includes stimulating a phrenic nerve with a pacing electrode at a location proximate a target treatment location, ablating tissue at the target treatment location with a treatment element, obtaining a heart audio signal with an audio sensor positioned proximate the target treatment location, and determining whether phrenic nerve stimulation (PNS) is present based as least in part on the obtained heart audio signal. A processor may be used to compare an amplitude of the obtained heart audio signal to a predetermined threshold amplitude. The processor may determine that PNS is present if the amplitude of the obtained audio signal is greater than the threshold amplitude. If PNS is present, ablation of the tissue may continue at the current or greater energy level and/or at the current treatment location without injuring the phrenic nerve.

Abstract: Cardiac resynchronization therapy (CRT) delivered to a heart of a patient may be adjusted based on detection of a surrogate indication of the intrinsic atrioventricular conduction of the heart. In some examples, the surrogate indication is determined to be a sense event of the first depolarizing ventricle of the heart within a predetermined period of time following the delivery of a fusion pacing stimulus to the later depolarizing ventricle. In some examples, the CRT is switched from a fusion pacing configuration to a biventricular pacing configuration if the surrogate indication is not detected, and the CRT is maintained in a fusion pacing configuration if the surrogate indication is detected.

Abstract: A medical device and associated method control the delivery of a cardiac pacing therapy by selecting first and second pacing sites along a first ventricle of a patient's heart and delivering the pacing therapy by pacing the first ventricle using the first pacing site during the periods of a first ventricular pacing mode and using the second pacing site during periods of a second ventricular pacing mode. In one embodiment, the device determines activation times at multiple sites along a ventricle in response to pacing pulses being delivered to the opposite ventricle. A first pacing site is selected in response to the activation time determination. The device delivers the pacing therapy by pacing the first ventricle using the first pacing site during periods of the first ventricular pacing mode.

Abstract: An implantable medical device receives both heart sound and electrogram signals. A processor within the implantable medical device extracts physiologically relevant information from both the heart sound signal and the electrogram signal. Based on the extracted physiologically relevant information a set of pacing parameters is evaluated. In certain examples, the values of the pacing parameters may be changed by the implantable medical device in response to the physiologically relevant information extracted from the heart sound signal and the electrogram signal.

Abstract: A medical device and associated method for controlling a cardiac pacing therapy sense a first cardiac signal including events corresponding to cardiac electrical events and a second cardiac signal including events corresponding to cardiac hemodynamic events. A processor is enabled to measure a cardiac conduction time interval using the first cardiac signal and control a signal generator to deliver a pacing therapy. A pacing control parameter is adjusted to a plurality of settings during the pacing therapy delivery. A hemodynamic parameter value is measured from the second cardiac signal during application of each of the control parameter settings. The processor identifies an optimal setting from the plurality of settings and solves for a patient-specific equation defining the pacing control parameter as a function of the cardiac conduction time interval.

Abstract: Cardiac resynchronization therapy (CRT) delivered to a heart of a patient may be adjusted based on detection of a surrogate indication of the intrinsic atrioventricular conduction of the heart. In some examples, the surrogate indication is determined to be a sense event of the first depolarizing ventricle of the heart within a predetermined period of time following the delivery of a fusion pacing stimulus to the later depolarizing ventricle. In some examples, the CRT is switched from a fusion pacing configuration to a biventricular pacing configuration if the surrogate indication is not detected, and the CRT is maintained in a fusion pacing configuration if the surrogate indication is detected.

Abstract: A medical device and associated method control the delivery of a cardiac pacing therapy by selecting first and second pacing sites along a first ventricle of a patient's heart and delivering the pacing therapy by pacing the first ventricle using the first pacing site during the periods of a first ventricular pacing mode and using the second pacing site during periods of a second ventricular pacing mode. In one embodiment, the device determines activation times at multiple sites along a ventricle in response to pacing pulses being delivered to the opposite ventricle. A first pacing site is selected in response to the activation time determination. The device delivers the pacing therapy by pacing the first ventricle using the first pacing site during periods of the first ventricular pacing mode.

Abstract: A medical device and associated method control the delivery of a cardiac pacing therapy including selecting left ventricular pacing sites for delivering the therapy. The left ventricular pacing sites are selected by delivering pacing pulses to a patient's left ventricle at multiple pacing sites one at a time and determining right ventricular activation times in response to the pacing pulses being delivered at each of the pacing sites. A left ventricular pacing site is selected in response to the determined right ventricular activation times.

Abstract: Techniques are described for detecting conduction abnormalities in a heart of a patient. In particular, an IMD may be configured to obtain electrical signals corresponding to cardiac activity of the heart of the patient and periodically analyze a most recent electrical signal of the obtained electrical signals to detect an electrical conduction abnormality of the heart. The IMD adjusts a frequency at which the most recent electrical signal is analyzed based on at least one physiological parameter of the patient. For example, the IMD may increase the frequency at which the most recent electrical signal is analyzed when a heart rate parameter has significantly changed and the number of detected premature ventricular contractions (PVCs) is greater than or equal to a threshold number. In this manner, the most recent electrical signal is analyzed at a higher frequency in situations in which conduction abnormalities are more likely.

Abstract: A medical device and associated method classify candidate pacing electrode sites for delivering pacing pulses to a patient's heart. A first morphology template is established and stored in memory of the device. A processor is configured to determine a cardiac signal morphology in response to delivering pacing pulses at a candidate pacing site in a first heart chamber. The processor compares the determined cardiac signal morphology to the first morphology template. The pacing site in the first heart chamber is classified in response to the comparing of the determined cardiac signal morphology and the first morphology template.